Powered table for hospital bed

ABSTRACT

AN ELECTRICALLY POWERED HYDRAULICALLY DRIVEN RETRACTABLE TABLE. A TABLE INTENDED TO BE MOUNTED ON A HOSPITAL BED AND IS CONSTRUCTED SO THE PATIENT, PRESUMABLY BEING PHYSICALLY UNABLE TO AMBULATE, MAY EASILY STOW THE TABLE OR RETURN IT TO A USABLE POSITION. THE TABLE SURFACE IS CONSTANTLY MAINTAINED IN A HORIZONTAL POSITION, I.E., IN A USABLE POSITION, IN A STOWED POSITION, AND WHEN TRAVELING FROM ONE POSITION TO THE OTHER.

POWERED TABLE FOR HOSPITAL BED Filed July 10. 1970 3 Sheets-Sheet 1 INVENTOR. JAMES M. ROWE H J. M. E

POWERED TABLE FOR HOSPITAL BED Filed July 10. 1970 5 Sheets-Sheet m INVENTOR.

JAMES M ROWE BY I IZMWM:

3,618,145 POWERED TABLE FUR HOSPITAL BED James M. Rowe, Rte. 1, Newcastle, Box 56C, Forrest City, Ark. 72335 Filed July 10, 1970, Ser. No. 53,866 Int. Cl. A47b 23/00 US. Cl. -332 Claims ABSTRACT OF THE DISCLOSURE An electrically powered hydraulically driven retractable table. A table intended to be mounted on a hospital bed and is constructed so the patient, presumably being physically unable to ambulate, may easily stow the table or return it to a usable position. The table surface is constantly maintained in a horizontal position, i.e., in a usable position, in a stowed position, and when traveling from one position to the other.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to bed tables and more particularly to tables for securement to a bed structure having a powered stowing capability.

(2) Description of the prior art The critical floor space in a typical hospital room seemingly has provoked many individuals to conceive a novel table. Tables for this purpose generally are attached to the bed structure, each in its own peculiar fashion with the intended purpose being that the table is readily available for use by the patient and at other times it may be conveniently stowed so as not to interfere with the routine care and treatment of the patient and at the same time occupy a minimum of floor space.

Patents pertaining to tables of the above description that are known by the applicant to exist are: The Sneed Pat. No. 1,043,638; the Rush et al. Pat. No. 2,193,647; the McLean et al. Pat. No. 2,483,920; the Woody Pat. No. 2,535,112 and the Black et al. Pat. No. 3,207,099. The Sneed 1,043,638 patent discloses a device that can be stowed underneath the bed; however, the table surface is displaced from a horizontal plane requiring the table surface to be completely free of any objects prior to being moved to the stowed position. The table surfaces in the Rush et al. 2,193,647 and the McLean et al. 2,483,920 also must be tilted when stowed. The table surfaces of the Woody Pat. 2,535,112 and the Black et al. 3,027,099 maintain a horizontal position; however, these table surfaces merely swing to one side of the bed where they may possibly interfere with the care and the treatment of the patient and also reduce the usable floor space within the room.

SUMMARY OF THE INVENTION The present invention is directed towards overcoming the heretofore-mentioned and other disadvantages in prior devices. The important features of the present invention are:

(A) The table surface is constantly maintained in a horizontal position, i.e., in a usable position, in a stowed position and when traveling from one position to the other. The particular advantage of this feature obviously is that certain patients physical condition may require immediate attention. In this event, when the table is in a usable position, i.e., extending across the bed over the patient, objects on the table surface need not be removed and the table can be quickly moved to a stowed position or a semi-stowed position.

Bfildlti Patented Nov. 9, 1971 (B) The table of the present invention is stowed under the bed so as not to occupy any floor space in addition to the floor space occupied by the bed. In this regard, a semistowed position may be any one of an infinite number of positions between the normally usable position and the fully stowed position, as just described.

(C) The table of the preesnt invention is power operated. The power pack is connected to any convenient wall outlet having suitable voltage, such as volts and the voltage is stepped down to a relatively safe amplitude, i.e., six volts or the like, so that in the event of a malfunction, the likelihood of the patient or other such persons operating the device receiving a dangerous jolt is minimized.

The present invention includes the typical table surface which may be rotated about a vertical axis when in usable position and a locking device which stabilizes the table surface in at least three positions: first, the preferred position, where the table extends across the bed so the patient can be elevated in the typical fashion so as to have ready access to food, etc., placed on the table surface, the patient preferably being in a semi-reclining position. Second, a position extending outwardly from the bed at from said first position. Third, a position extending toward the foot of the bed in a position whereby the longitudinal axis is substantially parallel with the longitudinal axis of the bed.

The table of the present invention is raised and lowered by a pair of articulating stanchions Which rotate about their pivots and are driven by a typical hydraulic double acting actuating cylinder. The table automatically moves transversely to a stowed position beneath the bed by a second hydraulically operated double acting actuating cylinder.

A control head, comprising a single-pole double-throw switch attached to the end of a flexible cable, is provided for the patient to actuate the table from the stowed position to a usable position and to return it to the stowed position. The table surface cannot be raised or lowered until it is rotated about the vertical axis to a position having its longitudinal axis substantially parallel with the longitudinal axis of the bed. This is accomplished by a cam-actuated microswitch or the like which disables the operating mechanism when the table is across the bed, thus obviating the possibility of the table being inadvertently lowered against the patient.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view depicting the device of the present invention in an environmental arrangement wherein a portion of a typical hospital bed or the like is phantomized and the table of the present invention is securely attached thereto.

FIG. 2 is an end elevational view taken as on the line IIII of FIG. 1.

FIG. 3 is a sectional view taken as on the line IIL-HI of FIG. 2 showing the arrangement of the pivoting and sliding structure of the table surface.

FIG. 4 is a sectional view taken as on the line IVIV of FIG. 3.

FIG. 5 is a similar view to FIGS. 3 and 4 but showing the locking detent displaced, the table slidingly moved laterally and pivoted about the vertical axis substantially 90.

FIG. 6 is a sectional view taken as on the line VIVI of FIG. 2 wherein the two actuating cylinders are both in an extended position.

FIG. 7 is a similar view to FIG. 6 but showing the two actuating cylinders in a retracted position.

FIG. 8 is a schematic of the electrical system of the present invention showing the three solenoid-actuated control valves in a de-energized position with respect to the associated interconnecting tubing.

FIG. 9 is a schematic of the hydraulic system of the present invention showing the three solenoid operated control valves in a normal position, i.e., interconnecting tubing assumed to not have hydraulic fluid under pressure.

DESCRIPTION OF THE PREFERRED EMBODIMENT The powered table 11 of the present invention adapted for use with a hospital bed 21 includes a typical table surface T supported by a pair of articulating stanchions 13, 15 which are connected at the lower end thereof to a raise and lowering double actuating hydraulic cylinder 17 which moves the table T vertically from a position having proximity to the floor to an elevated position wherein it would be normally used.

The table 11 also includes a traversing mechanism 19 which moves the table surface T, the articulating stanchion 13, 15 and the hydraulic cylinder 17 laterally to a stowed position, as best viewed in FIG. 2 wherein the table T is shown in broken lines and character referenced by the letter T". It should be understood that the table 11 of the present invention is preferably fixedly mounted to a bed 21 as shown in FIGS. 1 and 2 or, if desired, it could be mounted on traversing structure, e.g., like in the McLean et al. Pat. No. 2,483,920 wherein the table is supported by uprights having rollers at the lower ends thereof which ridingly engage a track assembly so the table 11 can travel to and fro along the longitudinal axis of the bed 21, i.e., from the head 23 toward the foot (not shown). The bed 21 includes the typical head 23, the foot (not shown), the rails 25, 27 connecting the head 23 and foot (not shown), and the mattress 29.

The traversing mechanism 19 (FIG. 6) generally comprises a carriage assembly 31 which supports the lower ends of the articulating stanchions 13, 15, a pair of tubular guide members 33, 35 and a double actuating hydraulic cylinder 37.

A power pack 39 (FIGS. 2 and 6) is suitably attached to the bed structure in any conventional manner, i.e., removable bolts inserted through suitably drilled holes (not shown) in the bed structure and suitable flanges (not shown) on the power pack 39. FIGS. 8 and 9 schematically depict the various components housed within the power pack 39. The power pack 39 comprises a hydraulic pump 41 that is operated by an electric motor 43, a single-pole single-throw relay 45 having independently energized dual windings 47, 49, a stepdown transformer 51, a hydraulic fluid reservoir 53, a plurality of three position solenoid operated valves (preferably three in number) 55, 57, 59, a plurality of pressure regulated valves (preferably two in number 61, 63, a plurality of check valves (preferably two in number) 65, 67 and the necessary interconnecting hydraulic fluid conduits and electrical conductors substantially as shown in FIGS. 8 and 9.

From FIGS. 4 and 8 of the drawings it may be seen that a single-pole single-throw cam actuated interlock switch 69 (preferably a micro-type switch) is electrically interposed between the low voltage output of the transformer 51, i.e., approximately six volts, and the remaining electrical controls and/ or apparatus. In other words, the entire electrical system and hydraulic system are deactivated until the interlock switch 69 is closed, the reason for which will be more apparent when the remaining structure has been disclosed.

From FIGS. 1 and 8 of the drawings, it may be seen that a single-pole double-throw control switch 71, preferably spring loaded to a neutral position, is manually operated by the patient when desired to move the table T from a stowed position T" (FIG. 2) to a usable position, i.e., extending across the mattress 29 at a suitable elevation predetermined to be most convenient, and/or return the table T to a stowed position T". The control switch 71 is preferably received in a suitable clip (not shown) which is attached to the head 23 of the bed 21 in any well known manner. Accordingly, the control switch 71 may be removed from the clip (not shown) and positioned adjacent the patients hands (not shown) for more convenient operation by a patient who may have difficulty reaching the control switch 71 when it is in the clip. This is easily achieved since the switch 71 is attached to a flexible cable 72 (FIG. 1). Therefore, the switch 71 may be located at any convenient location within the limits of the length of cable 72.

Referring now to FIG. 8 of the drawings, it may be seen that the solenoid valves 55, 57, 59 are spring-biased to a neutral position N and are moved to an up position U by their respective windings 73, 75, 77 when the interlock switch 69 is closed and the control switch 71 is placed in the up position U. It should be understood that when the solenoid windings 73, 75, 77 are energized, the respective valves 55, 57, 59 are displaced toward the right as when viewed in FIGS. 8 and 9. The solenoid valves 55, 57, 59 are moved to a down position D when their respective windings 79, 81, 83 are energized. The solenoid windings 79, "81, 83 displace their respective valves 55, 57, 59, when energized, to the left as viewed in FIGS. 8 and 9. The windings 79, 81, 83 are energized when the interlock switch 69 is closed and the control switch 71 is placed in the down position D. It should be noted that the relay 45 is energized when the interlock switch 69 is in a closed position and the control switch 71 is placed in either the up or down position, accordingly, the motor 43 operates during the up or down cycle and drives the pump 41 which delivers hydraulic fluid under pressure to the hydraulic system as viewed in FIG. 9, The pressure regulated valves 61, 63 are spring-biased to a neutral position N and are moved to a pressure position P when the pressure in the hydraulic line exceeds a predetermined pressure, the purposes for which will be more apparent when the remaining structure has been disclosed.

From FIGS. 1 and 2 of the drawings, it may be seen that the articulating stanchions 13, 15 support the table surface T and that the stanchion 15 is offset outwardly from the stanchion 13 to allow movement from a vertical position of the stanchions 13, 15 to a horizontal position wherein the table T moves from the usable position downwardly to the position T, depicted by broken lines in FIG. 2. The upper ends of the stanchions 13, 15 have a portion thereof bent to an angle substantially 90 forming a respective pair of upper pintles 85, 87. It should be noted that the pintle 85 is directed outwardly (FIGS. 2 and 3) and the pintle 87 is directed inwardly. The pintles 85, 87 are pivotally attached to a pivot housing 89, as best viewed in FIGS. 2 and 3. The pivot housing 89 comprises a pair of tubular members 91, 93, the inside diameter of each being slightly greater than the outside diameter of the tubular pintles 85, 87. The members 91, 93 are .fixedly attached, as by welding or the like, in a parallel spaced apart relationship, to a platelike member 95. The pintles 85, 87 are inserted through their respective tubular members 91, 93 and are pivotally attached thereto in any suitable manner, i.e., true arc snap rings circumferentially engaging respective suitably positioned annular recesses (preferably one adjacent each end of the tubular members 91, 93) in the pintles 85, 87.

The table T is secured as with rivets 97 through suitably aligned apertures to a bolster 99, or a trucklike member, which ridingly engages an elongated channel 101, as best viewed in FIGS. 3, 4 and 5. The channel 101 'has the normal U-shaped cross section centrally thereof which provides a broad or first horizontal surface 103 and in addition has a pair of outwardly directed flange members 105, 107 respectively having second and third horizontal surfaces 106, 108. The bolster 99 has a pair of downwardly directed support members 109, 111 which straddle a broad roller 113 that is rotatably attached thereto as with an axle 115. The bolster 99 also includes a pair of downwardly directed support members 117, 119 coextensive with the sides thereof, each of which rotatably support a respective relatively narrow roller 121, 123 in any typical manner such as by axles 122, 124 respectively which are directed inwardly from their respective support members 117, 119, substantially as depicted in FIGS. 3, 4 and 5.

From FIG. 3 of the drawings, it may be seen that the broad roller 113 ridingly engages the upwardly directed face portion of the first horizontal surface 103 of the channel 101 and that the narrow rollers 12], 123 ridingly engage their respective downwardly directed face portions of the second and third horizontal surfaces 106, 108 of the flange members 105, 107 respectively of the channel 101. It should be understood that the table surface T is rectangular in shape whereby the greater dimension extends across the bed 21 when the table T is in its usable position as shown in FIG. 1. Further, the bolster 99 is preferably secured to the table T between the end 125 (see FIG. 2) and the lateral centerline thereof. This off center location of the bolster 99 creates a torque which tends to produce rotation in a counterclockwise direction as when viewed in FIGS. 4 and 5. The applied torque urges the roller 113 downwardly against the surface 103 and urges the rollers 121, 123 upwardly against their respective surfaces 106, 108 of the channel 101.

Each end of the flange members 105, 107 has an up turned portion 127 which engages a horizontal platelike member 129 of the bolster 99, thus acting as stops for limiting the travel of the bolster 99 along the channel 101, i.e., preventing the bolster 99 from becoming disengaged from the channel 101. From FIGS. 3, 4 and of the drawings, it may be seen that the channel 101 is pivotally attached to the pivot housing 89 by a pivot bolt 131 inserted through an aperture 133 in the surface 103 of the channel 101 and an aperture 135 in the platelike member 95 of the pivot housing 89. The platelike member 95 of the pivot housing 89 is sandwiched between a pair of thrust bearings 137, 139 and sandwiched between the thrust bearing 139 and a locknut 141 is an annular pivot lock plate 143.

The pivot lock plate 143 preferably is keyed to the shank portion of the pivot bolt 131 in any well known manner and has a plurality of radially disposed notches 145 (preferably three in number) each being displaced substantially 90 one from the other. The aperture 133 is located centrally of the longitudinal axis adjacent the end of the channel 101 which is in proximity to the end 125 of the table T and the pivot bolt 131 extends downwardly through the aperture 133 preferably being fixedly attached to the channel 101, as by welding or the like. The radial notches 145 are designed to receive the protruding end of a locking detent 14-7.

The locking detent 147 comprises an elongated steel rod being bent substantially as depicted in FIG. 3, i.e., the one end which engages the notch 145. The elongated portion is disposed substantially 90 and extends into the drawing board when viewed in FIG. 3. The elongated portion is pivotally secured to suitable support structure 141-9 which is suitably attached as by welding or the like to the platelike member 95 of the pivot housing 89. The other end of the locking detent 1 17 terminates at a pivot lock release knob 143 (FIG. 2) which the patient manually rotates, thus causing the locking detent 147 to move downwardly as viewed in FIG. 5. When the locking detent 147 is in the position shown in FIG. 5, i.e., disengaged from the radial notch 145, the table T may be pivoted about the pivot bolt 131 as from the position depicted in FIG. 4 to a position depicted in FIG. 5.

A leaf spring 151 shaped substantially as depicted in FIG. 3 has the one end thereof fixedly attached to the platelike member of the pivot housing 89 in any well known manner, such as spot welding or the like. The other end of the spring 151 terminates at a ring portion 153 which circumferentially engages the protruding end of the locking detent 1 17, urging the locking detent 147 to a locking position, substantially as shown in FIG. 3. When the locking detent 147 is engaged with the notch 145, the table T is in a locked position since the pivot lock plate 143 is keyed to the pivot bolt 131 which is fixedly attached to the channel 101.

The preferred three radial notches provide a capability for locking the table T in three positions: first, extending across the bed 21 with the longitudinal axis thereof substantially perpendicular to the longitudinal axis of the bed 21 substantially as viewed in FIGS. 1 and 2; secondly, extending outwardly from the bed 21 at 180 from said first position; and thirdly, extending toward the foot (not shown) of the bed 21 in a position whereby the longitudinal axis thereof is substantially parallel with the longitudinal axis of the bed 21- This position provides the patient with a table T when he desires to sit toward the foot (not shown) of the bed 21 with his feet and legs dangling toward the floor. It should be understood that the table T may be slidably moved along its longitudinal axis, i.e., the bolster 99 ridingly engaging the channel 101 as previously described, a distance coextensive the length of the channel 101 while the table is in any of the above described locking positions. Further, additional notches 154 could be included to enable the table T to be locked in additional positions as desired.

The cam actuated interlock switch 69 (FIGS. 4 and 5), having a protruding plunger 155, is actuated, i.e., contacts closed and/or opened, by the roller 121 as it runningly and ridingly travels along the surface 106 of the flange 105. It should be understood that the switch 69 is thusly engaged only when the table surface T has been placed in the preferred positions as described above, i.e.,

- extending toward the foot of the bed 21, and the table T has been moved along its longitudinal axis toward the head 23 of the bed 21, i.e., the bolster 99 being urged to runningly and ridingly travel along the channel 101, in a manner previously described, to a point on the channel 101 whereby the platelike member 129 engages the up turned portion 127 of the flange member 105. At this time, the roller 121 engages the protruding plunger 155, thus actuating the switch 69. The plunger 155 of the switch 69 extends through a suitably aligned aperture 157 in the platelike member 95 of the pivot housing 89. The switch 69 is removably attached to the platelike member 95 of the pivot housing 89 in any well known manner, e.g., machine screws threaded through suitably aligned drilled and tapped holes (not shown). A suitable electrical cable 159 (FIG. 4) provides the necessary electrical interconnections for the switch 69, which interconnections and switch are schematically depicted in FIG. 8.

The table 11 is suspended below the mattress 29 of the bed 21 by a pair of downwardly extending platelike members 161, 163 which are suitably positioned and preferably fixedly attached to the rails 25, 27 in any well known manner, e.g., rivets 165 inserted through suitably aligned apertures in the members 161, 163 and their respective rails 25, 27, as best viewed in FIGS. 1 and 2. The platelike members 161, 163 straddle and support the two parallel spaced apart tubular guide members 33 35. The members 33, 35 are fixedly attached, as by welding or the like, at the ends thereof to the platelike members 161, 163.

The carriage assembly 31 comprises four tubular members 167, 169, 171, 173 fixedly held together as by welding or the like, each being fixed parallel one with the other in a spaced apart relationship by four vertical platelike members 175, 177, 179, 181. The two platelike members 175, 177, the planes of which are perpendicular to the longitudinal axis of the bed 21, are parallel one with the other and the two platelike members 179, 181, the planes of which are substantially parallel with the longitudinal axis of the bed 21, are parallel one with the other. The upper two tubular members 167, 169, having an inside diameter slightly greater than the outside diameter of their respective guide members 33, 35, slidingly circumferentially engage their respective guide member 33, 35. Thusly, the carriage assembly 31 may be moved freely to and fro along the guide members 33, 35.

The upright portion of the stanchions 13, being shaped substantially as depicted in FIGS. 1 and 2, each have an inwardly directed substantially 90 bend at the lower ends thereof, forming a lower pair of pintles 183, 185 (FIG. 6) respectively. It should be understood that the two lower tubular members 171, 173 have a parallel spaced apart distance substantially equal to the parallel spaced apart distance of the two tubular members 91, 93 of the pivot housing 89 and which receive the upper pintles 85, 87 of the respective stanchions 13, 15. This equal spaced apart distance, plus the fact that the stanchion 15 is offset outwardly from the stanchion 13, allows arcuate movement of the table surface T from the uppermost usable height to the lower position T and at the same time the table surface T is maintained in a substantially horizontal position. The lower tubular members 171, 173, having an inside diameter slightly greater than the outside diameter of the lower pintles 183, 185, pivotally encircle their respective pintles 183, 185 allowing the pintles 183, 185 to pivot freely.

The pintles 183, 185 extend inwardly beyond the tubular members 171, 173 of the carriage assembly 31 a short distance and terminate at a pair of respective lift arms 187, 189. The lift arms 187, 189, being identical one with the other, each comprise an elongated relatively short length of bar steel or the like fixedly attached, as by welding or the like, at the lower ends thereof to their respective pintles 183, 185. The lift arms 187, 189 are positioned With the longitudinal axes thereof parallel one with the other preferably aligned so that they extend from their respective pintles 183, 185 at an angle between the vertical and horizontal in a direction toward the head 23 of the bed 21 when the table surface T is in its highest position, substantially as lift arm 189 is depicted in FIG. 1.

The upper end of the lift arms 187, 189 are pivotally attached to a horizontally disposed raise and lowering control link 191 in any well known manner, as by pivot pins 197. The control link 191, formed from an elongated length of bar steel or the like, extends horizontally toward the head 23 of the bed 21 from the lift arm 189 a distance substantially equal to the span between the lift arms 187, 189, thence terminating at a right angularly disposed fixedly attached drive rod 193, as best viewed in FIG. 6. The drive rod 193, formed from round steel stock or the like, is caused to be substantially rigid, with respect to the control link 191, by incorporating a gusset plate 195 which is preferably welded along the adjacent surfaces to the control link 191 and the drive rod 193, as best viewed in FIG. 6.

The outer end of the drive rod 193 is pivotally connected to the end of an actuating rod 199 of the raise and lowering hydraulic cylinder 17, in any well known manner, e.g., the drive rod 193 inserted through a transversal drilled hole in the outermost end of the rod 199 and pivotally secured thereto as with true are snap rings (not shown) circumferentially engaging a pair of annular recesses (not shown) in the rod 193 adjacent each side of the rod 199. The raise and lower cylinder 17 is positioned substantially horizontal (FIG. 1), with the longitudinal axis thereof substantially parallel with the longitudinal axis of the bed 21, at a height substantially midway between the two upper tubular members 167, 169 and the two lower tubular members 171, 173.

The body of the cylinder 17 has attached at one end thereof an attachment clevice 201 which straddles a supporting lug 203. The attachment clevice 201 of the cylinder 17 is pivotally attached to the supporting lug 203 in a conventional manner, i.e., a clevice bolt (not shown) inserted through suitable apertures in the clevice 201 and the lug 203 and is removably secured by a cotter pin (not shown), as best viewed in FIG. 6. The supporting lug 203 is fixedly attached, as by Welding or the like, subjacent the tubular member 167 and extends downwardly to the clevice 201 with its plane being substantially parallel with the longitudinal axis of the bed 21. It should be understood that the table surface T is at a raised height when the cylinder 17 is extended, as shown in FIGS. 1 and 6. Further, the table surface T is at its lowest height as depicted in broken lines in FIG. 1 when the cylinder 17 is in a retracted position, substantially as shown in FIG. 7. The table surface is character referenced by the letter T" when it is thusly positioned.

The traversing hydraulic cylinder 37 has an attachment clevice 205 attached at the one end thereof and an actuating rod 207 at the other. The outermost end of the actuating rod 207 terminates at an attachment clevice 209 which is suitably attached to a supporting lug 211 in a conventional manner, i.e., a clevis pin 213 passing through suitably drilled holes in the clevis 209 and the supporting lug 211 typically secured as with a cotter pin (not shown). The supporting lug 211 is fixedly attached to the vertical platelike member 179 of the carriage assembly 13, as by wleding or the like, with its plane positioned substantially perpendicular to the longitudinal axis of the bed 21. The cylinder 37 is positioned substantially intermediate the tubular guide members 33, 35 and at substantially the same height as the members 33, 35 as best viewed in FIGS. 1 and 2. The clevis 205 straddles a supporting lug 215 and is pivotally attached thereto in a conventional manner, i.e., a clevis pin 217 passing through suitably drilled apertures in the clevis 205 and the lug 215 and is typically secured as with a cotter pin (not shown). The supporting lug 215, being positioned with its plane substantially parallel with the plane of the lug 211 and preferably in alignment with the lug 211 so that an extension of the centerline thereof passes through the centerline of the lug 211, is fixedly attached, as by welding or the like, to the plate-like member 163, as best viewed in FIG. 6.

It should be understood that the cylinder 37 moves the table surface T from its lowermost position T (FIG. 2), traversely to a stowed position T". In this regard, the carriage assembly 31 slides freely along the guide members .33, 35, substantially as from the position shown in FIG.

6 to that shown in FIG. 7.

Referring now to FIGS. 8 and 9 of the drawings wherein it may be seen that a pair of conductors 219, 221 provide the electrical input, e.g., volts AC connected in the conventional manner as with an electrical plug (not shown), to the power pack 39. The conductors 219, 221 energize the step-down transformer 51 which has a low voltage output, i.e., six volts AC or the like. A common conductor 223 extends from a junction of the conductor 219 and the one side of the transformer 51 to one side of the two windings 79, 73 of the solenoid valve 55, thence to the two windings 81, 75 of the solenoid valve 57, thence to the two windings 83, 77 of the solenoid valve 59, thence to one side of both the windings 47, 49 of the relay 45, thence to one side of the motor 43.

The interlock switch 69, being actuated in a manner previously described, completes the circuit from the transformer 51 to the control switch 71. When the control switch 71 is placed in the up position, the circuit is closed between a pair of contacts 225, 227 of the control switch 71 and current flows along a common conductor 229 which carries current to the other side of the windings 73 of the solenoid 55, thence to the other side of the windings 75 of the solenoid valve 57, thence to the other side of the windings 77 of the solenoid valve 59, thence to the other side of the windings 47 of the relay 45. A conductor 231 is connected at the one end to the conductor 221 and at the other to a contact 233 of the relay 45. A conductor 235 is connected at the one end thereof to a contact 237 of the relay 45 and at the other end to the other side of the motor 43. There fore, when the switch 71 is moved to the up position, i.e., closing contacts 225, 227, the solenoid valves 55, 57, 59 move to the right as viewed in FIGS. 8 and 9 and the relay 45 is energized, closing the contacts 233, 237 which in turn energizes the motor 43. The motor 43, being energized, drives the pump 41 in a typical manner.

The pump 41 is connected to the reservoir 53 by a conduit 239 on the inlet side and to the solenoid valve 55 by a conduit 241 on the outlet side. The solenoid valve 55 has a conduit 243 leading to the reservoir 53. The solenoid valves 55, 57 are interconnected with a conduit 245 and the valves 57, 61 are interconnected with a conduit 247. The cylinder 37 and the valve 61 are interconnected with a conduit 249. The cylinder 17 and the valve 61 are interconnected with a conduit 251. The chamber behind the piston 253 of the cylinder 37 and the valve 63 are interconnected with a conduit 255. The check valve 67 and the valve 63 are interconnected with a conduit 257 and a bypass conduit 261. The output side of the check valve 67 and the solenoid valve 59 are interconnected with a condiut 263. The solenoid valve 59 and the reservoir 53 are interconnected with a conduit 265. The chamber behind the piston 268 of the cylinder 17 and the pressure regulated valve 63 are interconnected with a conduit 269.

Assuming the table surface T to be in the stowed position as depicted by T" (FIG. 2) and the control switch 71 in the up position as above described, the pump 41 is pulling hydraulic fluid from the reservoir 53 through the conduit 239 and delivering the fluid under pressure through the conduit 241 to the solenoid valve 55, thence through the conduit 245 to the solenoid valve 57, thence through the conduit 247 to the valve 61, thence through the conduit 249 to the front side of the piston 253 of the cylinder 37. It should be understood that the pres sure regulated valve 61 is set to operate at a higher pressure than required to extend the cylinder 17, therefore, the piston 253 of the cylinder 37 moves to the right as viewed in FIG. 9 until it reaches the limit of its travel, which causes the pressure in the conduit 247 to build up and operate the valve 61, i.e., move it to the left as viewed in FIG. 9.

The extending of the cylinder 37 moved the carriage assembly 31 (FIG. 6) traversely (or out from under the bed 21) so that the table surface T is at the intermediate position designated as T in FIG. 2. As the piston 253 of the cylinder 37 moved to the right (FIG. 9), the hydraulic fluid in the chamber behind the piston 253 exits the cylinder 37 through the conduit 255 to the valve 63, thence through the conduit 257 and the check valve 67, thence through the conduit 263 to the valve 59, thence through te conduit 265 to the reservoir 53.

Since the valve 61 moved to the left (FIG. 9), the pressure in the conduit 247 is now diverted within the valve 61 to the conduit 251 that leads to the head or front side of the piston 268 of the cylinder 17, thus driving the piston 268 upwardly as viewed in FIG. 9.

As the cylinder 17 extends the rod 199 (FIG. 6), the control link 191 is moved horizontally, causing the lift arms 187, 189 to rotate clockwise, as viewed in FIG. 1. The pintles 183, 185 pivot about their respective tubular members 173, 171, thus articulating the stanchiions 13, 15 in a clockwise direction as viewed in FIG. 1 until the table scrface T reaches its usable height, as viewed in FIG. 1. The switch 71 is now moved to a neutral position which causes the solenoid valves 55, 57, 59 to return to their respective neutral positions, under the influence of springs, not shown, the relay 45 is de-energized, i.e., interrupting of the circuit between the contacts 233, 237 and the motor 43 is de-energized, which causes the pump 41 to cease functioning. It should be understood that when the solenoid valve 57 goes to the neutral position, the pressure in the conduit 247 is maintained, accordingly, the pressure within the cylinders 37, 17 is maintained, preventing hydraulic fluid from bleeding in the system in which case the table surface T might gravitate downwardly. From FIG. 8 of the drawings, it may be seen that the switch 71, being a single-pole double-throw switch, has a third contact 267. A common conductor 269 is connected at the one end thereof to the contact 267 and the other end connects the other side of the windings 79 of the solenoid valve 55, the other side of the windings 81 of the solenoid valve 57, the other side of the windings 83 of the solenoid valve 59 and the other side of the windings 49 of the relay 45.

From FIG. 9 of the drawings, it may be seen that the solenoid valves 55, 59 are interconnected with a conduit 271 and that the pressure'regulated valve 61 and the check valve 65 are interconnected with a conduit 273. The output side of the check valve 65 is connected to a junction of the conduit 247 by a conduit 2'75 and the solenoid valve 57 is in communication with the revervoir 53 through a conduit 277.

The table surface T may be moved to the stowed position T by first pivoting the table surface T about a vertical axis to a position whereby the longitudinal axis thereof is substantially parallel with the longitudinal axis of the bed 21 and the table T extends from the stanchions 13, 15 toward the foot of the bed 21. The next preliminary action required prior to the table surface T being able to be operated is that the table surface T must be slidingly moved toward the head 23 of the bed 21 in a manner previously described, but the action of which closes the switch 69. The patient then moves the switch 71 to the down position which closes the contacts 225, 267, sending current along the conductor 269, thus energizing the windings 79, 81, 83 of their respective solenoid valves 55, 57, 59 and the windings 49 of the relay 45. The energized windings 79, 81, 83 causes the solenoid valves 55, 57, 59 to move to the left as viewed in FIGS. 8 and 9.

Since the windings 49 of the relay 45 are energized the contacts 233, 237 are closed which deliver the line voltage to the motor 43 in like manner as described above. The pump 41 is pulling hydraulic fluid from the reservoir 53 through the conduit 239 and delivering hydraulic fluid under pressure through the conduit 241 to the solenoid valve 55, thence upward through the conduit 271 to the solenoid valve 59, thence upward through the conduit 263 to the junction of the bypass conduit 261, thence downward through the conduit 261 to the pressure regulated valve 63. It should be understood that the valve 63 is identical in structure as the valve 61 and the above description for the valve 61 pertains to the valve 63 likewise. The hydraulic fluid under pressure leaves the valve 63 through the conduit 269 and drives the piston 268 of the cylinder 17 downwardly, as viewed in FIG. 9, causing the table surface T to arcuately travel to the intermediate position identified as T' in FIGS. 1 and 2.

When the cylinder 17 has fully retracted the pressure buildup in the conduit 261 causes the valve 63 to operate, i.e., move to the right as viewed in FIG. 9, diverting hydraulic fluid under pressure into the conduit 255. This causes the piston 253 of the cylinder 37 to move to the left, as viewed in FIG. 9. Accordingly, both cylinders 17, 37 are fully retracted as viewed in FIG. 7. It should be understood that the hydraulic fluid that was displaced in the cylinder 17 as the piston moves to the retracted position exited the cylinder 17 through the conduit 251 to the valve 61, thence downwardly through the conduit 273 to the check valve 65, thence through the conduit 275 to the junction of the conduit 247, thence through the conduit 247 to the valve 57, thence downwardly through the conduit 277 to the reservoir 53. Further, the hydraulic fluid being displaced when the cylinder 37 was retracted exits the cylinder 37 through the conduit 249 and enters the valve 61, thence through the conduit 247 to the solenoid valve 57, thence downwardly through the conduit 277 to the reservoir 53. The switch 71 is now placed in the neutral position which allows the solenoid valves 55, 57, 59 to return to their neutral positions and the relay 45 is de-energized, thus interrupting the current to the motor 43.

When the electrical system has been de-energized, as above described, the neutral position of the valves 55, 57, 59 block displacement of hydraulic fluid, accordingly, the table surface T will be held in any desired position when the solenoid valves 55, 57, 59 are in a neutral position. In this regard, following the sequence involved in moving the table surface T to an upward position, the hydraulic fluid under pressure in the conduit 247 maintains the valve 61 in an operative position, i.e., moved to the left as viewed in FIG. 9. It should be noted that when the switch 71 is moved to the down position and the solenoid valves 55, 57, 59 are energized or moved to the left as viewed in FIG. 9, the hydraulic fluid under pressure in the conduit 247 is diverted through the valve 57 to the conduit 277 (in communication with the reservoir 53) which allows the pressure in the conduit 247 to bleed into the conduit 277, thus the spring biased valve 61 will return to a normal position, i.e., to the right as viewed in FIG. 9.

Following the downward sequence, hydraulic fluid is maintained under pressure in the conduits 261, 263 which holds the valve 63 in an operative position, i.e., to the right as viewed in FIG. 9. When the switch 71 is placed in the up position and the solenoid valves 55, 57, 59 are energized or moved to the right as viewed in FIG. 9, the hydraulic fluid under pressure in the conduits 2 61, 263 is diverted through the valve 59 to the conduit 265 (in communication with the reservoir 53) which allows the hydraulic fluid under pressure to bleed into the conduit 265, thus the spring biased valve 63 will return to a normal position, i.e., to the left as viewed in FIG. 9.

Although the invention has been described and illustrated with respect to a preferred embodiment thereof, it is to be understood that it is not to be so limited since changes and modifications may be made therein which are within the full intended scope of this invention.

I claim:

1. A powered table for a hospital bed comprising guide means adapted for mounting beneath the hospital bed and extending transversely thereof, carriage assembly means slidably mounted on said guide means, pivot housing means, a horizontal table, means mounting said table on said pivot housing means for pivoting movement of said table about a vertical axis including a transverse position over the bed and a position lengthwise relative to the bed, stanchion means pivotally mounted adjacent the lower end thereof on said carriage assembly means and pivotally connected adjacent the upper end thereof to said pivot housing means for movement between an upright position and a lower substantially horizontal position to carry said table between an upper position above the level of the bed and a lower position below the level of the bed, first actuating means mounted on said carriage assembly means and connected to said stanchion means for moving said stanchion means between said upright and lower horizontal positions, and second actuating means connected to said carriage assembly means for moving said carriage assembly means to move said table when in said lower position between a position alongside the bed and a position beneath the bed.

2. The powered table of claim 1 in which said means mounting said table on said pivot housing means includes means movably mounting said table for endwise horizontal linear movement thereof between extended and retracted positions.

3. The powered table of claim 1 in which said means mounting said table on said pivot housing means comprises a channel including an upwardly facing surface and a pair of downwardly facing surfaces parallel with and on opposite sides of said upwardly facing surface, bolster means fixedly mounted on the underside of said table in offset relationship from the center of said table towards one end 12 thereof, a first roller rotatably mounted on said bolster means and rollingly engaging said upwardly facing surface, and a pair of rollers rotatably mounted on said bolster means on opposite sides of said first roller and rollingly engaging said downwardly facing surfaces.

4. The powered table of claim 2 in which is included interlock means mounted on said means mounting said table on said pivot housing means and operable responsive to movement of said table to prevent actuation of said first actuating means unless said table is in said retracted position and in said position lengthwise relative to said bed.

5. The powered table of claim 1 in which said first actuating means includes first hydraulic cylinder means and means operably coupling said first hydraulic cylinder means to said stanchion means for movement thereof, hy draulic supply means, and in which said second actuating means includes second hydraulic cylinder means operably coupled to said carriage assembly means, said first and second actuating means additionally including electro-hydraulic control means including control switch means operable to a down position for causing the hydraulic fluid to be directed first to said first hydraulic cylinder means to cause said table to move from said upper position to said lower position alongside the bed and then to be directed to said second hydraulic cylinder means to cause said table to move from said lower position alongside the bed to a position beneath the bed and said control switch means operable in an up position for causing the hydraulic fluid to be directed first to said second hydraulic cylinder means to cause said table to move from a position beneath the bed to said lower position alongside the bed and then to be directed to said first hydraulic means to cause said table to move from said lower position alongside the bed to said upper position.

6. The powered table of claim 5 in which said stanchion means includes a pair of spaced apart stanchions respectively having horizontally extending pintles provided at the lower ends thereof; and in which said means operably coupling said first hydraulic cylinder means to said stan- I chion means includes a pair of lift arms respectively fixedly attached to said pintles, a control link pivotally attached to said lift arms, and drive rod means operably coupling said first hydraulic cylinder means to said control link.

7. The powered table of claim 6 in which said guide means includes a pair of parallel spaced apart tubular guide members and in which said carriage assembly means includes a pair of tubular members respectively slidably engaging said tubular guide members with said tubular guide members extending therethrough.

8. The powered table of claim 7 in which said table is pivotable about a vertical axis to an extended position relative to said transverse position over the bed, and in which is included lock means for selectively locking said table in said transverse position, said extended position and said position lengthwise relative to the bed.

9. A powered table for a hospital bed comprising a pair of guide members, means mounting said guide members in spaced apart substantially parallel relationship extending beneath said bed and transversely thereof; a carriage assembly including an upper pair of tubular members respectively slidably encircling said guide members, a lower pair of parallel spaced apart tubular members and means rigidly joining said tubular members to one another; a pair of stanchions respectively having an upper pair of oppositely extending pintles adjacent the upper ends thereof and respectively having a lower pair of inwardly extending pintles adjacent the lower ends thereof with said lower pair of pintles being respectively received in said lower pair of tubular members for movement of said stanchions between an upright position and a lower substantially horizontal position, pivot housing means including a substantially horizontal plate-like member and a pair of tubular members fixedly attached to said plate-like member and respectively receiving said upper pair of pintles to establish with said stanchions and said lower tubular members a parallelogram to maintain said platelike member substantially horizontal when said stanchions are moved between said upright and horizontal positions, one of said stanchions being offset outwardly from the other of said stanchions to permit said stanchions to be in substantial horizontal alignment with one another when said stanchions are in said lower position, a channel including an upwardly facing surface and a pair of downwardly facing surfaces parallel with and on opposite sides of said upwardly facing surface, means pivotally mounting said channel on said plate-like member for pivot of said channel about a vertical axis, a table bolster means fixedly mounted on the underside of said table in offset relationship from the center of said table towards one end thereof, a first roller rotatably mounted on said bolster means and rollingly engaging said upwardly facing surface, a pair of rollers rotatably mounted on said bolster means on opposite sides of said first roller and rollingly engaging said downwardly facing surfaces, when said stanchions are moved between said upright position and said horizontal position said table being moved thereby between an upper position above the level of said bed and a lower position below the level of said 'bed, first actuating means mounted on said carriage assembly and connected to said stanchions for moving said stanchions between said upright and lower horizontal positions, and second actuating means connected to said carriage assembly for moving said carriage assembly to move said table when in said lower position between a position alongside said bed and a position beneath said bed.

10. The powered table of claim 9 in which said first actuating means includes first hydraulic cylinder means and means operably coupling said first hydraulic cylinder means to said stanchions for movement thereof, hydraulic supply means, and in which said second actuating means includes second hydraulic cylinder means operably coupled to said carriage assembly, said first and second actuating means additionally including electro-hydraulic control means including control switch means operable to a down position for causing the hydraulic fluid to be directed first to said first hydraulic cylinder means to cause said table to move from said upper position to said lower position alongside the bed and then to be directed to said second hydraulic cylinder means to cause said table to move from said lower position alongside the bed to a position beneath the bed and said control switch means operable in an up position for causing the hydraulic fluid to be directed first to said second hydraulic cylinder means to cause said table to move from a position beneath the bed to said lower position alongside the bed and thento be directed to said first hydraulic means to cause said table to move from said lower position alongside the bed to said upper position.

References Cited UNITED STATES PATENTS 1,862,237 6/1932 Pepler 108-49 2,612,422 9/1952 Sarkus 108-49 3,021,185 2/1962 Kowalczyk 297-143 BOBBY R. GAY, Primary Examiner G. MOORE, Assistant Examiner US. Cl. XR. 10849; 297-l 62 

